The Fragile Families and Child Wellbeing Study - a birth cohort study of unwed parents and their children - will provide previously unavailable information on: (l) the economic and social conditions of unwed fathers and mothers, (2) relationships in fragile families, including extended kin, (3) child and parental wellbeing, and (4) the role of labor markets, and government policies in promoting father involvement, good parenting, and healthy child development. The study addresses three NICHD priority areas - nonmarital childbearing, fathering, and welfare reform - and brings these three areas together in a unique fashion. The study will follow a cohort of new parents in sixteen U.S. cities, stratified by different labor market conditions and different welfare and child support policy regimes. The sample will be representative of the racial and ethnic composition of each city and will also be nationally representative of all nonmarital births to parents residing in cities with populations over 100,000. A comparison group of married parents will also be followed. In-hospital interviews will be conducted with both mothers and fathers at the time of birth, and follow-up interviews will be conducted when the child is 9, 18, 30, and 42 months old. Data on child wellbeing will be collected each year from the mother, and in-home assessments of child wellbeing will be carried out at the 30-month interview. Data on up to two siblings (and half siblings) will also be collected. The study will provide a rich set of data that will be useful to a broad range of researchers. It will also provide policy-makers with important information on the implementation of welfare and child support reforms and how they play out in different labor market environments.